1. Field of the Invention
This invention relates to refining crude oil. This invention particularly relates to improving processing of heavy residual crude oil during refining.
2. Background of the Prior Art
Refining is the process of treating raw hydrocarbon and its conversion into lighter, higher octane number components. The development of the internal combustion engine led to the production of gasoline and diesel fuels. While simple gasoline was sufficient for automobiles, it was the airplane that created a need for high-octane aviation gasoline and then for jet fuels. In addition to fuels, refineries now produce a variety of products such as lubricants but also including many required as initial feed-stocks for the petrochemical industry.
During the course of refining crude oil, the crude oil and resultant process streams may be subjected to distillation, thermal cracking, catalytic conversion, and various other treatments. Cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules (e.g. light hydrocarbons) by the breaking of carbon-carbon bonds in the precursors.
During distillation, the higher boiling compounds are separated from compounds often having a higher molecular weight and greater viscosity. After removal of the distillate, the resulting bottoms may be subjected to further cracking until, finally, all that is left is bitumen or coke. Even these compounds have value in today's markets, but most often it would be desirable to produce more rather than less of the comparatively low boiling and more valuable distillates.
Unfortunately, as the viscosity of the heavy distillation bottoms increases, there is a corresponding increase in the difficulty of handling (moving and further refining) such heavy hydrocarbons. In some circumstances, the bottoms can even solidify thereby blocking fluid movement. It would be desirable in the art of refining hydrocarbons to be able to reduce the viscosity of heavy residual crude oil economically and without introducing materials which could complicate further processing.